Metrics

Zibri contains a pretty basic metrics service. It collects up to 60 snapshots. If you need more than that you should use an external service, like prometheus.

Collecting data

For collecting data the service provides a collect method:

import { MetricsServiceInterface, inject, ZIBRI_DI_TOKENS } from 'zibri';
// ...
const metricsService: MetricsServiceInterface = inject(ZIBRI_DI_TOKENS.METRICS_SERVICE);
await metricsService.collect();
// ...
Copy

You will however most likely use the provided ScrapeMetricsCronJob which collects a snapshot every 5 seconds. See registering cron jobs.

Exposing a basic dashboard

By default, your project contains a metrics.hbs file that is used to display the data of the metrics service.

You can simply create a new controller and expose it there:

// src/controllers/metrics.controller.ts
import { Controller, Inject, ZIBRI_DI_TOKENS, Metric, Get, Response, HtmlResponse, MetricsSnapshot, GlobalRegistry, MetricsServiceInterface } from 'zibri';

import renderBasePageTemplate from '../templates/pages/base-page.hbs';
import renderMetricsTemplate from '../templates/pages/metrics.hbs';

@Controller('/metrics')
export class MetricsController {
    constructor(
        @Inject(ZIBRI_DI_TOKENS.METRICS_SERVICE)
        private readonly metricsService: MetricsServiceInterface
    ) {}

    // optional, to be used with an external tool like prometheus
    @Get()
    @Response.array(Metric)
    get(): MetricsSnapshot[] {
        return this.metricsService.getMetricSnapshots();
    }

    @Response.html()
    @Get('/dashboard')
    dashboard(): HtmlResponse {
        const content: string = renderMetricsTemplate({
            name: GlobalRegistry.getAppData('name') ?? '-',
            version: GlobalRegistry.getAppData('version') ?? '-'
        });
        const html: string = renderBasePageTemplate({ base: { title: 'Metrics Dashboard' }, content });
        return HtmlResponse.fromString(html);
    }
}
Copy

Now you can navigate to http://localhost:3000/metrics/dashboard and see it in action.